Explosive expansion of formation in lifts for forming an in situ oil shale retort

Patent · Tue Apr 17 04:00:00 EST 1984

OSTI ID:6784141

Ricketts, T E

An in situ oil shale retort is formed by excavating a lower level void adjacent the bottom boundary of a retort site in a subterranean formation, leaving a zone of unfragmented formation within side boundaries of the retort overlying the void. At least a portion of the overlying zone is explosively expanded downwardly towards the void in a plurality of lifts. Vertical columnar explosive charges are placed in each lift and detonated in a single round with a time delay between successive lifts sufficient for formation of the first lift to move out of the way and not interfere with initial explosive expansion of formation in the next successive lift. Preferably, the explosive charges in a second lift are detonated after detonation of explosive charges in a first lift with a time delay in the range of from about five to thirty milliseconds per foot of burden distance of the charges in the second lift. When plural lifts above the first lift are explosively expanded, it is preferred that the time delays progressively increase from the bottom up.

• Assignee: Occidental Oil Shale Inc.
• Patent Number(s): US 4443036
• OSTI ID: 6784141
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
040300 -- Oil Shales & Tar Sands-- Drilling
Fracturing & Mining
040401* -- Oil Shales & Tar Sands-- In Situ Methods
True & Modified
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
CHEMICAL REACTORS
COMMINUTION
DECOMPOSITION
DETONATION WAVES
DISTILLATION EQUIPMENT
ENERGY SOURCES
EQUIPMENT
EXPLOSIVE FRACTURING
EXPLOSIVES
FOSSIL FUELS
FRACTURING
FRAGMENTATION
FUELS
IN-SITU PROCESSING
IN-SITU RETORTING
MATERIALS
MINING
OIL SHALE MINING
OIL SHALES
PROCESSING
RETORTING
RETORTS
SHOCK WAVES
TIME DEPENDENCE